Previously the genus Meles was considered to be monospecific. Recent morphological and genetic studies supported the separation of Meles into three species, two on the Asian mainland and M. anakuma endemic to Japan (Abramov 2002, 2003; Abramov and Puzachenko 2005, 2006). Fossils of Meles were excavated from a Late Middle Pleistocene in southern Japan (Kawamura et al. 1989, Kawamura 1991). It is considered that the genus arrived in Japan along a south-easterly route through the Korean Peninsula, based on its absence on Hokkaido Island and its occurrence on the other three main islands of Japan.

Justification:
Japanese Badger is listed as Least Concern in the light of presumed large populations, occurrence in a wide variety of habitats including peri-urban areas, and inference (based on information overlapping the early part of the last three generation [25-year] assessment window) that it is not declining at a rate which would qualify for listing even as Near Threatened. However, the occupied range has obviously shrunk since 1978 in 45 of the 46 prefectures in which it occurs. Japanese Badger is negatively affected by the invasive Northern Raccoon Procyon lotor which is now widespread in Japan (Ikeda et al. 2004), but the extent to which it is driving Badger declines is unknown. Specific research is needed to quantify the threat posed, and whether this badger is declining fast enough to warrant categorisation as Near Threatened or, conceivably, even higher.

Japanese Badger is endemic to Japan, where it is found on the large islands of Honshu, Kyushu and Shikoku, and on Shodoshima but no other small islands (Kaneko 2009). The distribution was estimated to cover about 29% of country (about 126,000 km²) by a 2003 survey for the Ministry of the Environment. It has been recorded over 37-2,000 m a.s.l. (Y. Kaneko pers. comm. 2014).

The Environmental Agency of Japan (1979) reported that there were many Japanese Badgers in Fukui (Honshu), Miyazaki and Oita (Kyushu) but fewer in Ibaraki, Osaka, Chiba and Tokyo (Honshu) prefectures. In 2003, the Ministry of the Environment reported in a national survey on the natural environment that Badger geographic range was obviously shrinking in 45 of 46 prefectures compared with the 1978 survey, especially in Nara and Chiba (Honshu) prefectures while only one prefecture (Ehime in Shikoku) reported increase. The recorded distribution area is about 29% of the country (about 126,000 km²) with an estimated 7% reduction in the 25-year period.

Japanese Badger is classified as a 'game species' in Japan. The numbers hunted each year declined from 7,000 to fewer than 2,000 between the 1970s and the late 1980s; this trend might have been caused by a decrease of interest in badgers as game animals (Y. Kaneko pers. comm. 2006). Although present scientific surveys are not sufficient to define population trends or density, the latter was estimated as 4 adults/km² in Tokyo suburb from seven years' capture-recapture result.

Although Japanese Badger is little studied ecologically, several surveys were conducted in three typical habitats in Honshu: evergreen broad-leaved forest in Yamaguchi; subalpine conifer plantation in Nagano (Mount Nyugasa); and conifer plantation/countryside mosaic in a Tokyo suburb (Hinode-town).

Body size, life cycle and reproductionJapanese Badger is far smaller than Eurasian Badger M. meles. the total body length in adults (over 2 years old) is 78.7 ± 4.9 cm in males and 72.0 ± 2.3 cm in females (Tokyo; Kaneko et al. 1996). Smaller badgers were recorded in the southern evergreen forest population (66.8 ± 2.7 cm in males and 60.4 ± 2.4 cm in females; Yamaguchi, Tanaka 2002). Japanese Badger’s smaller skull is accompanied by a decrease of sexual size dimorphism (except in canine size) compared with the continental species (Abramov 2005). Body weight varies much between individuals and seasons; for April-July: 7.7 ± 1.3 kg in males and 5.4 ± 0.8 kg in females in Tokyo (Kaneko and Maruyama 2002), 5.7 ± 0.4 kg in males and 4.4 ± 0.6 kg in females in Yamaguchi (Tanaka 2002). Female’s parturition is from 2 years of age. It occurs in mid-April in Tokyo, and in mid-March to April in Yamaguchi. The average litter is 2.5 ± 1.2 cubs (range: 1-4 cubs; Kaneko 2001) and 2.3 cubs in Yamaguchi (Tanaka 2002). Copulation is from April, just after parturition in April and implantation of blastocysts is delayed until February (Kaneko 2001). Tanaka (2002, 2005, 2006) reported Japanese Badger as nocturnal, with activity almost ceasing in January and February; animals then remain in theirs setts most of the time, with about 3 °C lower body temperature.

Food, home range and coverJapanese Badger feeds on earthworms from spring to autumn in the subalpine zone (Yamamoto 1991, 1995), in evergreen forest (Tanaka 2002) and in a Tokyo suburb (Hinode-town; Kaneko 2001, Kaneko et al. 2006). It is also known to eat other items: berries and beetles in summer in all three habitats and, in autumn in the Tokyo suburb, animals switched from worms to persimmons (tree fruit).

Social structureUnlike Eurasian Badger, there is no male-female bond for rearing cubs (based on direct observation in a Tokyo suburb; Ito 1992). Both female and male adult home ranges were solitary in Yamaguchi (Tanaka 2001). It seems that male badgers are solitary but bond temporarily with one or several females in the mating season. At this season in the Tokyo suburb (Kaneko et al. 2014) and Yamaguchi (Tanaka et al. 2002), each male badger's range overlapped with those of 2-3 females. Tanaka suggested that intra-sexual territoriality in the Yamaguchi population may differ from the large social group or pair in Eurasian Badger. Scent marking in the Tokyo suburb (Kaneko 2009) using the border latrines may be effective information about badger presence and oestrus status in low density populations because there are few opportunities for badgers to encounter each other and no badgers met at latrines.

Japanese Badger population and distribution has been shrinking since the late 20th century, mainly because of intensive development and agriculture (Y. Kaneko pers. comm. 2006). In addition, there is an unknown level of threat from the invasive carnivore Northern Raccoon Procyon lotor (Y. Kaneko pers. comm. 2006). Radio-tracking data from a Tokyo suburb showed that a breeding female was not able to use her breeding site in a year a Raccoon was present in her home range (Y. Kaneko pers. comm. 2014). In the western part of Honshu, Japanese Badger is more threatened by the high density of leg-hold traps set for Eurasian Wild Pig Sus scrofa and by habitat flagmentation through urbanisation, than by conflict with Northern Raccoon.

Japanese Badger is designated in local Red Data Lists in 11 out of 46 prefectures as Vulnerable (VU) in Hyogo,as Near Threatened (NT or C) in Chiba, Kagawa, Tokyo, Oita, Okayama, Osaka and Yamaguchi, and as Data Deficient (DD) in Aichi, Gunma and Tochigi. There have been some studies of its natural history but these are not sufficient to clarify the level of threat posed by Northern Raccoon Procyon lotor. A national distribution survey is undertaken by the Ministry of Environment every five years for this species, but is of limited accuracy: the survey is carried out mainly by interviewing local wildlife volunteers, rescue teams and hunters, and the reported badgers are sometimes misidentified Raccoon Dogs Nyctereutes procyonoides or Masked Palm Civets Paguma larvata.